module AbstractController::Helpers::ClassMethods

Public Instance Methods

clear_helpers() click to toggle source

Clears up all existing helpers in this class, only keeping the helper with the same name as this class.

# File lib/abstract_controller/helpers.rb, line 106
def clear_helpers
  inherited_helper_methods = _helper_methods
  self._helpers = Module.new
  self._helper_methods = Array.new

  inherited_helper_methods.each { |meth| helper_method meth }
  default_helper_module! unless anonymous?
end
helper(*args, &block) click to toggle source

The helper class method can take a series of helper module names, a block, or both.

Parameters

  • *args - Module, Symbol, String, :all

  • block - A block defining helper methods

Examples

When the argument is a module it will be included directly in the template class.

helper FooHelper # => includes FooHelper

When the argument is a string or symbol, the method will provide the "_helper" suffix, require the file and include the module in the template class. The second form illustrates how to include custom helpers when working with namespaced controllers, or other cases where the file containing the helper definition is not in one of Rails' standard load paths:

helper :foo             # => requires 'foo_helper' and includes FooHelper
helper 'resources/foo'  # => requires 'resources/foo_helper' and includes Resources::FooHelper

Additionally, the helper class method can receive and evaluate a block, making the methods defined available to the template.

# One line
helper { def hello() "Hello, world!" end }

# Multi-line
helper do
  def foo(bar)
    "#{bar} is the very best"
  end
end

Finally, all the above styles can be mixed together, and the helper method can be invoked with a mix of symbols, strings, modules and blocks.

helper(:three, BlindHelper) { def mice() 'mice' end }
# File lib/abstract_controller/helpers.rb, line 96
def helper(*args, &block)
  modules_for_helpers(args).each do |mod|
    add_template_helper(mod)
  end

  _helpers.module_eval(&block) if block_given?
end
helper_method(*meths) click to toggle source

Declare a controller method as a helper. For example, the following makes the current_user controller method available to the view:

class ApplicationController < ActionController::Base
  helper_method :current_user, :logged_in?

  def current_user
    @current_user ||= User.find_by_id(session[:user])
  end

   def logged_in?
     current_user != nil
   end
end

In a view:

<% if logged_in? -%>Welcome, <%= current_user.name %><% end -%>

Parameters

  • method[, method] - A name or names of a method on the controller to be made available on the view.

# File lib/abstract_controller/helpers.rb, line 48
      def helper_method(*meths)
        meths.flatten!
        self._helper_methods += meths

        meths.each do |meth|
          _helpers.class_eval "            def #{meth}(*args, &blk)
              controller.send(%(#{meth}), *args, &blk)
            end
", __FILE__, __LINE__ + 1
        end
      end
inherited(klass) click to toggle source

When a class is inherited, wrap its helper module in a new module. This ensures that the parent class's module can be changed independently of the child class's.

# File lib/abstract_controller/helpers.rb, line 21
def inherited(klass)
  helpers = _helpers
  klass._helpers = Module.new { include helpers }
  klass.class_eval { default_helper_module! unless anonymous? }
  super
end